Pipe hanger clamp stop



March 21, 1961 Filed Sept. 5, 1958 P. C. SHERBURNE PIPE HANGER CLAMPSTOP 3. Sheets-Sheet 1 INVENTOR.

PHILIP C. SHERBURNE ATTORN March 1961 P. c. SHERBURNE 2,975,995

PIPE HANGER CLAMP STOP Filed Sept. 3, 1958 3 Sheets-Sheet 2 INVENTOR.

K a g PHILIP c. SHERBURNE March 21, 1961 P. c. SHERBURNE PIPE HANGERCLAMP STOP 3 Sheets-Sheet 3 Filed Sept. 3, 1958 v WQ\ INVENTOR.

nited States Patent Ofiice PIPE HANGER CLAMP STOP Philip C. Sherburne,Rumtord, R.I., assignor to Grinnell Corporation, Providence, R.I., acorporation of Delaware Filed Sept. 3, 1958, Ser. No. 758,802

4 Claims. (Cl. 248-54) This invention relates generally to improvementsin spring devices which exert a substantially constant supporting forceon a load movable vertically within a limited range, and morespecifically relates to a removable clamp stop for such devices.

A spring support typical of the type referred to above is the hangerknown in the trade as the constant support hanger for supporting pipingwhich is subject to vertical travel due to changes in temperature. Sincethe weight and travel of the piping to be supported determine the hangersize and there are many weights and travels there is a large number ofhanger sizes available to the public. Each of these is designed tosupport piping within a given load range fora given travel.

In the normal course of events, the purchaser of such a pipe hangercalculates in advance and as accurately as possible the weight, traveland direction of travel between hot and cold conditions for theparticular section of pipeing he desires to support and'orders from thehanger manufacturer a hanger which includes this Weight and travelwithin its range. Thereupon, the hanger manufacturer prepares this sizeof ha'nger or selectslitfrom those in stock, adjusts it to the load andtravel specified by the customer and places on its frame two marks toindicate the positions of the parts for the cold and hot positions ofthe pipe. The 'hangers are then sent out from the factory with the partsimmobilized in their cold positions so as to permit installation in'thesystem. This immobilization of the parts involves deflecting the springand maintaining it deflected.

The prior practice in immobilizing the hangers was to pass a boltthrough one end of a metal strap to the hanger frame and bolt the otherend of this strap to the lever connecting the spring to the crank arm.For structural reasons there were generally only two or three bolt holesin the lever so that the hanger could be immobilized in only a limitednumber of positions, it being impractical to drill the holes speciallyfor each hanger. The result, upon removal of the strap afterinstallation, was generally found to be that the hanger required a finalreadjustment of considerable degree to make up for the error which wasimposed by the limited number of immobilizing positions. Furthermorebecause of the close spacing between frame, strap and lever the placingof the bolts was an awkward, inconvenient, and time consuming procedure.Moreover, due to the spacing of the holes, rather delicate adjustment ofthe lever was required to align a hole in the lever with a hole in thestrap.

In constrast to these prior devices applicants device is accurate to onehalf the base width of one of the teeth on a lock plate which will bedescribed, and this distance is so small that no readjustment isnecessary when the lock plate is released. Further, because the lockplate and other parts in applicants device are generally on the outsideof the hanger frame the immobilization and release of the hanger aresimple procedures.

After the installation has been completed and tested Patented Mar. 21,1961 and the system placed in operation it is desirable that the hanger,under its hot working conditions, be adjusted so that the indicator pinwill be at the hot or H point previously computed and stamped in theframe. This is true in hangers employing any immobilizing devices and itmeans that the hangers usually require a final adjustment for the hotworking conditions to furnish the desired support. Consequently, after aperiod of time, when the system is shut down for maintenance (duringwhich the system is tested with water under pressure) the hangers veryrarely return to their original cold position. One reason for this isthat the final hot working adjustment usually has reoriented theoperating range of the hanger within its total range. If, during themaintenance period, the hangers can be immobilized for the testing inthis new cold position, then upon restoring the system to operation itwill be found that the hangers will be operating at their correct Hposition. However, this has not been possible with the prior practice ofusing straps and bolts, becausesof the likelihood that none of thelimited number of immobilizing positions will-correspond to the new coldposition, so that considerable movement has been required to align abolt hole in the strap with a bolt hole in the lever. This means thateach time the system using hangers with the prior devices is shut downthe position of the pipe with respect to the hangers must be adjusted"so that the pipe will again be properly supported under the water loadat the required alignment toprevent unneces sary stress in the systemand to permit the system to drain properly after the water test, andthen upon restoration of the system to operation, an additionaladjustment must be made to bring the hanger back to its proper hot or Hposition. I V

Because the present invention permits a hanger to be immobilized in anyoperating or cold position without extensive movement, none of the abovedescribed additional adjustments are necessary when a system is shutdown and then restored to operation.

An object of thisinvention is to provide an improved clamp stop whichwill permit a hanger to be accurately pre-set. I

Another object of this invention is to provide a stop which will notrequire the removal of material from the hanger spring lever and thuspossibly cause structural weakening.

Still another object of this invention is to provide a clamp stop whichwill fix a hanger in any desired cold position so that upon restorationof the hanger to operation subsequent corrective adjustments will not bere quired.

Other .objects will appear hereinafter.

The present invention and its objects will be better understood by thoseskilled in the art from the follow-' ing description taken with thedrawings which accompany this specification and in which:

Figure 1 is a perspective view partly broken away showing a constantsupport hanger immobilized in the cold position by the prior art boltedlocking device;

Figure 2 is a cross-sectional detail of the prior locking device takenalong the line 22 of Figure 1;

Figure 3 is a side elevation sectional view showing a constant supporthanger with the locking device of the present invention fastened theretoand locking s'aid hanger at an intermediate position;

Figure 4 is a partial view of the apparatus of Figure 3 as viewed frombelow; a

a Figure 5' is an end sectional view taken along line 55 of Figure 3 andshowing a clamp stop at each end of the indicatorpin; f a r Figure 6 isan exploded perspective of the components of the clamp stop itself.

Referring now more particularly to the drawings, Figs. 1 and 2 whichshow the prior art device have been included to assist in anunderstanding of the prior proposals inasmuch as no patents orliterature show them, as'far as is known. In these figures the numeral'1 indicates a standard form of constant support spring hanger which hasa frame 2 with a slot 3 through which extends an indicator pin 4fastened to a bell crank 4a. To lock said hanger, a bolt 5 is passedthrough hole 6 in the frame and screwed into threaded hole 7 of strap 8(see Fig. 2). A bolt is also passed through any one of holes 10 in thelever 11 (fastened to an end plate, not shown, on the outer end of thehanger spring) and then screwed into the more convenient of threadedholes 12 in the strap 8. It is thus seen that it would requireconsiderable movement to align a hole 10 with a hole 12 before thehanger rod 11 would be immobilized and that much material is removedfrom the lever 11 during the formation of holes 10.

Turning now to the present invention clearly shown in Figures 3 to 6inclusive, the frame of the hanger 101 is indicated at 102. Through theside portions 103 and 104 of the frame are slots 105 and 106 throughwhich indicator pin 107, fastened to a bellcrank lever 107a of thehanger, extends. During the operation of the hanger the position of theindicator pin will vary between the C (cold) and H (hot) points (seen inFigure 3) of the slot 105.

To immobilize the hanger the following procedure is set out. A cap 108having a hollowed portion 109 is fitted over the end of pin 107.Extending outward from the base of the cap is a threaded rod 110. At thejunction of the cap and rod is a shoulder portion 111 having teeth 112on its outwardly exposed face. The preferred form of this inventionshows the rod, shoulder portion and cap as a single unit, but it isobvious that the rod 110 may be a separate unit inserted through thebase of the cap 108 and retained there and that shoulder portion 112 maybe a separate unit bored so as to fit over the rod 110 against the baseof cap 108. A slotted plate 113 is placed over the rod with the 'slot114 in the plate straddling the rod and having the centerline of itsslot superimposed over the centerline of the adjacent slot 105 in theframe. Fastening this plate to the frame are threaded bolts 115 whichare passed through holes 116 in the plate and into tapped holes in theframe. On the inner surface of the plate are teeth 117 which are equalin size and spacing to the teeth 112 of the shoulder portion. When thenut 118 is screwed down on the rod 110 into abutment with washer 119,the cap and shoulder portion will be drawn outwardly causing the teeth112 of the shoulder portion to interlock with the teeth 117 of the plate113, thereby locking the indicator pin 107 and thus immobilizing thehanger.

To free the hanger after any necessary adjustments have been performed,bolts 115 are removed and the entire locking assembly lifted clear thusleaving the indicator pin 107 free to move in slot 105 as the hangerlever 107a moves with load movements.

It will be understood by those skilled in the art that the hollowedportion 109 may be placed in the end of the indicator pin 107 and aprojection instead of cap 108 extended from member 111 and inserted insaid hollowed portion, to obtain the described locking action, withoutdeviating from the spirit of said invention.

I claim:

1. In a constant support hanger of the type described having a frame anda lever member pivoted thereon, a clamp stop assembly comprising anelongated toothed surface on said frame extending along the path traced7 by a point on said lever member when the lever swings about its pivot,a clamp member having a point thereon, a projection on one of saidmembers at its said point,

a socket on the other said member at its said point receiving saidprojection, said clamp member also having a toothed surface presented tosaid toothed surface on said frame, and means for drawing said toothed sr faces into interlocking engagement, whereby the lever ay be fixed withrespect to the frame at any selected p sition in its range of swing.

2. In a constant support hanger of the type described wherein saidhanger has a frame member and a lever pivoted thereon with an indicatorpin extending therefrom through a slot in said member, a clamp stopdevice comprising a cap extending through said slot in the frame memberand engaging the end portion of said indicator pin, a projecting memberextending externally of said cap, a flatshoulder extendingperpendicularly outwardly of said projecting member at the latters baseand sub stantially parallel to the frame member, said shoulder havingclosely spaced teeth on its outermost surface, a slotted member fastenedto said frame member externally of and substantially parallel to saidshoulder with its slot superimposed over the slot in the frame andreceiving said projecting member through its slot, said slotted memberhaving teeth on its surface nearest the shoulder and complementary tothe teeth on said shoulder, and means cooperative with said projectingmember for forcing said teeth on said shoulder into engagement with said.teeth on said slotted member.

3. In an adjustable spring device having a frame member and a leverpivoted thereon with an indicator pin extending therefrom through a slotin said member, a clamp stop device comprising a cap extending throughsaid slot and engaging the end portion of said pin, a threaded rodextending externally of said cap, a fiat shoulder portion extendingperpendicularly outwardly of said rod at the latter's base andsubstantially parallel to the frame member, said shoulder portion havingclosely spaced teeth on its outermost surface, a slotted memberfastened. to said frame member externally of and substantially parallelto said shoulder portion with its slot superimposed over the slot in theframe and receiving said rod through its slot, said slotted memberhaving teeth on its surface nearest the shoulder portion andcomplementary to the teeth on said shoulder portion, and a threaded nuton said rod for forcing said teeth on said shoulder portion intoengagement with said teeth on said slotted member.

4. In an adjustable spring device having a frame member and a leverpivoted thereon with an indicator pin extending therefrom through a slotin said member, a clamp stop device comprising a cap extending throughsaid slot and engaging the end portion of said pin, a threaded rodextending externally of said cap, a fiat shoulder extendingperpendicularly outwardly of said rod at the latters base andsubstantially parallel to said shoulder portion and integral with saidrod and said cap, said shoulder having closely spaced teeth on itsoutermost surface, a slotted member fastened to said frame memberexternally of and substantially parallel to said shoulder portion withits slot superimposed over the slot in the frame and receiving said rodthrough its slot, said slotted member having teeth on its surfacenearest the shoulder and complementary to the teeth on said shoulder anda threaded nut on said rod for forcing said t eth on said shoulder intoengagement with said teeth n said slotted member.

References Cited in the file of this patent UNITED STATES PATENTS257,050 Munson Apr. 25, 1882 943,492 Turner Dec. 14, 1909 2,784,962Sherburne Mar. 17, 1957 2,929,594 Wood Mar. 22, 1960

